Telephone system.



A. ANDERSEN. TELEPHONEv SYSTEM. APPLICATION FILED oc.,24, 1913.

11,295,096. Patented Feb-25,1919.

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A. ANDERSEN. TELEPHONE SYSTEM. AFPLlcATloN 111.60 0cT.24.1913.

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A..A'NDEHSEN. TELEPHONE SYSTEM. ARPLICA'TI'ON FILED ocr.24, 1913. 1,295,096 I Patented Feb.1919.

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ALBERT .ANDERSIEEHYIQ OF CHICAGO, ILLINOIS, 'ASSIGNOR TO AUTOMATIC LECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

TELEPHONE SYSTEM.

Application filed October 24, 1913.

To all whom it may concern:

Beit known that I, ALBERT ANDERSEN, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented certain new and useful Improvements in Telephone Systems, of Which the following is a specification.

My invention relates'to improvements in telephone systems,` and has tor its object certain improvements in the construction and operation ot' the substation and central otiice apparatus en'iployed in such systems.

Among the. objects of my invention is the provision of a substation circuit inwhich theusual call signal or bell is omitted` the subscriber being signaled through the receiver, which is normally bridged across line through a condenser.

A second feature of my invention is the provision of an enunciator system by which any subscriber can automatically establish connection with a series ot enunciators or announcers.

A further t'eature of my invention is the i sired subscriber can not answer the telephone and will accordingly innnediately hang up his receiver and prevent the truuk lines being tied up for an unnecessary pcriod ot time.

A further feature of my invention is the provision of means whereby a subscriber can be automatically called trom the central otiice at. any predetermined time.

rThese and other objects of my invention will be more clearly understood by reference to the accompanying drawings` in which I have illustrated the same in connection with an automatic system of a well-known type.

Figures 1, 2 and P taken together represent diagitainmatically a connection between a calling and a called subscribers line. This connectlon is established in the Well-known manner by :neans of the individuallline switch C, the first selector E, the secondy se` Specification of Letters Patent.

. T. G. Martin No. 1419 ot' 1910.

Patented Feb. 25, 1919.

Serial No. 797,103.

line the receiver 2 is bridged across the line through the springs 112 and 110 and the condenser 5, whereby when the subscriber is called the ringing current passes through the receiver and thus this receiver acts as the calling signal. The impulse-transmitting device for controlling the automatic switches is represented diagrammatically by a pair of impulse springs 6 and 7 controlled by an impulse wheel 8, which latter may be controlled in the` well-known manner through the medium of a dial provided with linger holds in such a way that the impulse springs will be momentarily separated a number of times corresponding to the respcctive digits of the number of the called subscriber.

The subscribers individual switch C is of' the general type ot subscribers switch shown in British patent to R. 1V. James No. 26.301 of 1906, being, however, of the particular type disclosed in British patent to The master switch D is of the same general type as that disclosed in British patent No. :26,301 of 1906, referred tol above, being, however. of the particular type disclosed in said British patent No. 1419 of 1910. The function of the master switch, as is well known. is to maintain the plungers ot all the idle line switchesin position to engage the terminals of an idle trunk line.

The first selector switch E is of the gen` eral type of selector switch disclosed .in

kUnited States Letters Patent No. 815.321,

granted March 13, 1906, to Keith, Erickson and Erickson, except that the so-called side switch is omitted and the circuits are moditied so as to permit the switch to be operated in a twonvire system, in the manner -Y shown in British Patent No. 10,37 6 of 1912,

granted to T. G. Martin. Y

The second selector F is essentially the same as the selector E.

The connector switch ,l (Fig. 2) is of the same general type et connector switch as disclosed in United States Letters Patent No. 815,176, granted March 13, 1900, to Keith, VErickson and Erickson, the circuits, however,fl5cing modified to adapt the switch. to operate in a system in which the central oiiice apparatus is 'controlled by impulses delivered over the two sides of the line 1n series, in the manner shown in British Patent No. 10,376 of 1912, above referred to.

The substation A is the usual form of automatic substation including; the bell 88, which is normally bridged acros'i the line through the condenser 95. This substation is likewise provided with a relay 10iconnected in a-normally. open bridge across the line controlled by the `key L. This relay 10i is provided with a pair of interrupter springs 107, whereby it operates as a buzzer for the purpose of giving this special busy signal in a. manner to be hereinafter described.

The substation A2 is the same type as sub'- station A except in addition it has an interrup'ter rela connected in a. normally open bridge a ross the line controlled by a key similar to that of substation A. The called subscribers line may be provided with a substation like A or a substation like A2.

The enunciator apparatus H comprises the double-'wound relay 200`for placing a guarding potential on the private bank contact 26a, which preventsv more than one party from using the same enunciator at the saine time. There is also shown an amplifier or microphone repeater Hf comprising the coil 215 and microphone controlled thereby, whichmicrophone repeater is well known in the art. lThe impulses or sound waves transmitted over one circuit are received by a magnet 215 which operates the differential microphone. The impulses are thus repeated by the' `microphone in the circuit which contains th loud speaking receivers or reproduoers. These reproducers and ampliiiers can be of any desired 'type and may be similar to those shown in FrenchPatent No. 450,768 and British patents to- W. H. DerrimanI Nos. 21,812 and 21,814o''1911.

For the purpose of supplying battery current-for operating the apparatus in the eX- change andA for talking purposes there is shown a plurality of batteries B having one terminal grounded at G. Only one'battery, however is necessary in practice.

In order that my invention may be more clearly understood I will now explain how a party at the substation A may establish connectlon with the enunciator apparatus, or with a subscriber at the substation A. Since the automatic switching apparatus disclosed in this application is in general well known in the art and is fully described in the publications iereinabove referred to, it is not thought necessary to describe' in detail the manner in which these switchesA operate 'to establish the connections.

1When a subscriber, desiring to establish connection with an enunciator apparatus, removes his receiver from the switclrhook atthe substation A preparatory to making a call, an energizing circuit is closed through the line winding 13 of the individual switch `C and this switch is tripped in the wellknown manner to connect with the trunk extending to the selector E, which we will assume is idle at this time. The line relay 30 vof the selector switch E is thereupon energized, closing the circuit through the relay 34. The relay 34, upon energizing,'closes a holding circuit through the cutfoii' winding 12 oi the line switch C. The usual guarding ground potential is also supplied to the connector private bank contacts of the calling line as soon as the relay 34.- is energized. The enunciator apparatus H being connected to the contacts of the first level of the selector, the calling subscriber now operates his calling device for the digit 1, whereby the substation impulse springs 6 and 7 are separated once momentarily, breaking the circuit of the selector line relay 30. This single impulse'operates in the well-known manner to step the switch wipers up to the first level and then rotate the same onto the first contact in that level to which the enunciator apparatus H is connected. If the enunciator is not already in use, the-circuit .oi the switching relay 53 is closed in the well-known manner, and this relay 58, upon energizing, disconnects the line relay 30 from the line and extends the line connection to the apparatus H through the wipers 25, 26 and 27. The double-wound relay 200 thereupon becomes energized to send back a holding ground to take the place or" theusual ground G2, since the relay 34 is denergized when the line relay 30 is disconnected from the line. The newv holding circuit is traced from ground G30 through the springs 205, Contact 26, wiper 20, contact springs 64; and 64a and the relay 58 to battery B. The holding circuit for the winding 12 is also .traced Assuming now that the apparatus 1-1 was are iinally and there y kcontacts 26a which it engages provided with a uarding potential, which would be transmitted through the relay 66 and the springs v63 and 64, thereby preventing it iirom deenergizing. The rotary magnet, however,

denergizes when the springs 70 disengage,

' regardless of whether 'the relay 66'remains een;

` A, whose number is f energized lor not.

If the relay 66 remains energized, the circuit of the rotary magnet Willbeagain closed as soon as the armature drops back far enough to close the sprlngs 5 9 and 60. Thus the wipers are moved onto the next contacts, z'. e., contacts 25h, 26b and 527P,;and"owing to the fact that-there` is no ardingpotentiah on the private Contact ,relay 66 denergizes, thereby permanently breaking. the. circuit of the rotary magnet 29; However, as soon asV the wipers .comete rest after being rotated ofi' vthe engaged contact, .the cilrcuit of the doublewound relay 201 (which is similar to the relay 200) is closed from ground G31 'through the `lower windingn of said relay, contact 27 1, over the heavy conductors, through the telephone, back through the' contact 25b and the top winding'of the relay 201 to battery B. Upon the Irelay 201 becoming energized. a holding circuit.is provided from ground Gra3 throughthe springs-208, contact 26b and 'through the relay 58 and the winding 12 in multiple to battery B. This circuit is closed before the slow ,acting relay 34 has time to denergize to break the cilr-cuit of the switching relay 58. A busy circuit is also closed from `the busy machine Q through the` springs 209, condenser 210, contact 25",

through the calling subscribers telephone, back 'through the contact 27b and through ,the lower half of the relay 201 to ground. 'Upon the busy signal being heard-at the substation A, the receiver is"returned1t0 the switch-hook and the connection lrele'a'sed.

Assumingnow-that a subscriber at substation'A, instead of wishing to connect with the enunciator, wishes to make connection with'another subscribers line 'at substation 2220. The operations lfor the first digit are precisely the same as described for the digit 1 when connecting with the enunciator. By calling the digit 2, the wipers are raised two steps to a position opposite the second row or level of bank contacts in ywhich aire the terminals of trunk lines leading to agroup of the above-mentioned 'second selectors F. They then are rotated onto lthe iirst contacts in a manner already described and the rotatry magnet subscriber tion tothe connector J (Fig. 2).

When the calling device'is operated for the third digit 2, the circuit of the line relay 47 is momentarily broken twice to raise the Wipers of the Connector to the second level, and then when the calling subscriber operates his calling device Jfor the last digit 0, the connector line relay 47 operates to transmit ten impulses through the rotary magnet in series with the relay 74, whereby the shaft is rotated onto the contacts of the desired line.

The ringing current from the generator R is then supplied to the called line in the usual manner. When the called sulbscribegr renioves his receiver, or as soon thereafter as the ringer relay denergizes if it is energized at the time, the ringing current is cut oli and the called substation is provided with talking current.

It will now be explained how a subscriber, by operating the key L at his telpehone, may place asignaling tone upon his line which will indicate to the calling subscriber that the called party is out, or for various other reasons cannot answer the call, whereupon the calling subscriber will place his receiver on'the switch-hook and release the connection, whereby a trunk line will not be kept busy an unnecessary length ottime. The 'operations of the key L bridges the high resistance relay 104 across the line conductors 94 and 96. Should the subscriber at substation A be called at this time, a lcircuit is closed through the relay 104 during the intermittent periods that the relay 49 is in a denergized position. This energizing circuit for thev relay 104 extends from ground G1 Pthrough the back-bridge .relay 48, springs 89, springs 90, wiper 38, over the conductor 94, relay 104, springs 107, key L, thence back over the conductor 96, springs 91,'conductor- 83, wipers 36, springs 97, springs 99a, and through the relay 48 to battery B. The relay/'104 operates to break its own circuit at the springs 107 and thus operates to rap-.

idly interrupt the circuit, thereby placing a buzz or tone on the line of the calling subscriber every time the ringing relay deenergizes. l

The release of the connection is accomplished in the usual manner by the calling returning his receiver to the switch hook, whereby the switches are returned to their normal positions.

1t will now be explained how the apparatus K and the clock O are adapted to be connectedI .with a subseribers line to. ring'- his bell at a certain time. Opposite each numeral'there is a suitable contact point, such as shown at 155, with which the hour hand (which is made of a conducting material) is arranged to comeinto contact as it rotates. Connected to each contact 155 by means of lead 156 are one or more relays 122 having' one terminal connected to the battery lead 1GO. A key K is also provided, one side of which is grounded and the other connected in any suitable manner to a `contact associated with any of the numerals for the purpose of making electrical connection, by means ot both the hour and minute hands, with the relay 122. rlhese contacts maybe placed anywhere on the dial and the leads 156 connected to any contact, according to the hour a subscriber wishes to vhe caflledl T he relay 123 is a ringing relay 'and is energized by the energization ot the relay 122 from ground G23. It is thus seen that to call a subscriber, say at six oclock, the attendant connects certain springs of the relays 122 and 123 by means of leads 157, 158 and 159 to the normal conductors of the said subscribei"s line, and also connects'the relay 122 to the lead 156 and operates the key K. When the minute and hour hands are passing over the contacts 150 and 155, respectively, at the same time, a circuit is closed 'from ground G22 through the springs o1 the key through the minute and hour hands to the Contact 155, lead 15G and through the relay 122 to batteryB. The relay 122, upon energizing, places guarding potential on lthe private contacts ot' the connectors that have access to the linebeing called, said potential extending from ground G23 through the spinge 160 and 161.l vThe cut-oit winding 80 is also energized from the same point to* operate the armature 82 to close the contact of springs 91 and to disconnect the line switch trom the called line. The circuit of the relay 123 is also closed from ground G23 through thesprings 160 and 161 and through said relay to the battery lead 100. The relay energizes to bridge the ringing generator R across the line, which sends out alternating current to ring the bell at the substation A. There may be as many springs 162, 163 and 164 on the relays 123 and 122, respectively, as they are capable of controlling for the purpose ot' calling a plurality of subscribers, or iithere should be more subscribers to be called at a certain hour than one set o1" relays could handle, a plurality of said sets may be put into service. Furthermore, the metal contact 150 with which the minute hand connects may be of any suitable length, so as to prolong y the length of time that electrical connections are maintained to leepv the ringing relay 12E energized.

lt will thus be seen that l have devised a very useful system, and while l have illustrated the various features ot' my inven tion in connection with an automatic telephone system of a well-known type, it will,

Vof course, be understood that my invention system.

is not in any way limited to use in such a lt is obvious that the substation circuit could be employed with other forms et systems, either automatic or manual. Likewise, other modifications could be'made in the enunciator system and in connection with the other features of my invent-ion.

lVliat I claim as my invention is 1. In a telephone system, a calling and called line, a telephone for the called line, automatic progressively movable switching means for connecting the two lines in a talking circuit, means controlled by the calling subscriber for signaling Vthe called subscriber, said means comprising a bridge normally across said called line including `a re ceiver and a condenser, a pair of springs in said bridge controlled by-zfa switchhook, a transmitter, and means clontrolled by `the operation of the switch-hook for disconnecting said condenser from said bridge and connecting the transmitter in bridge with said receiver.

2. In a telephone system, a calling and -called line, a telephone for the called line,

automatic progressively movable switching means for connecting the two lines in a talking circuit, means controlled by the calling subscriber for signaling the called vsubscriber, said means comprising a bridge normally across said called line including a receiver and. a condenser, a pair of springs in said bridge controlled by a switch-hook, a transmitter, means controlled by the .operation of the switch-hook for disconnecting said ,condens/U from said bridge and connecting the transmitter in bridge with said receiver, and an impulse-transmitting device included in said bridge with said transmitter.

In a telephone system, a calling and a called line` a receiver and a condenser normally in bridge of said called line, auto-- matic progressively movable means for establishing a communicating circuit between said lines and for signaling said called line through said bridge, and a signaling apparatus bridged across the called line whereby a signal is transmitted automatically from the called line to the calling line when the communicating circuit is established.

4. ln a telephone system, a callingand a called line, a receiver and a Condenser noirmally in bridge ofsaid calledy line, auto matic progressively movable means for connecting the two lines and for signaling said calledvxline through said bridge, an interruptor ma gnet'bridged across the called line, and means for eiicrg'izing said magnet to thereby transmit a'sigiial back to the calling line.

5. ln a telephone system, a calling and a called line, a telephone for thelc'alledline, automatic progressivelii movable switching means for connecting the :two lines Vin. a

talking-circuit, means controlled by the calling subscriber for signaling the called subscriber, said means comprising a bridge normally across said called line including a receiver and a condenser, a pair of springs in said bridge controlled by a switch-hook, a transmitter, and means controlled by the operation of the switch-hook for disconnecting said condenser from said bridge and connecting the transmitter in bridge with said receiver, and other means associated with the called line for signaling the calling line.

6'. In a telephone system, a calling and a called line, a telephone for the called line, lautomatic progressively movable switching means for connecting the two lines in a talking circuit, means controlled by the calling subscriber for signaling the called sub- Scriber, said means comprising a bridge normally across said called line including a re- Y ceiver and a condenser, a pair of springs in said bridge controlled by a switch-hook, a transmitter, means controlled by the operation of the switch-hook for disconnecting said condenser from said bridge and conn ecting the transmitter in bridge with-said receiver, an impulse-transmitting device ineluded in said bridge with said transmitter, and other means associated with the called line for signaling the calling line.

7. In' a telephone system,'a calling and a called line, a receiver and a condenser normally in bridge of said called line, automatic progressively movablemeans for establish- .called line, a receiver and a condenseiwnoring a communicating circuit between said lines and -for signaling said called line through said bridge,'a signaling apparatus bridged across the called line whereby a signal is transmitted automatically from the called line to the calling line whei the communicating circuit is established,\and other means associated with the called line for signaling the called line to announce the time.

8. In a telephone system, a 'calling and a mally in bridge of 'said called line, means for connecting the two lines, and for signaling said called linethrough said bridge, an interrupter magnet bridged across the called line, means for energizing said magnet to thereby transmit a signal back to the calling line, and other means associated with the called line for signaling the called line to announce the time.

9.' In a telephone system, a calling line and .i called line, automatic prc'gressively movable means for connecting the two, a bridge ynormally across the called line including a receiver and condenser, a pair of springs in said bridge controlled by the switch hook, a transmitter, andmeans controlled by the operation of the switch hook for disconnecting said condenser from said bridge and connecting the transmitter in bridge with the receiver, and means across the called line for signaling the calling line.

l0. In a telephone system, a calling line and a called line, automatic progressively movable -means for connecting the two, a bridge normally across the called line including a receiver and condenser, a pair of springs in said bridge controlled by the switch hook, a transmitter, and means con- Itrolled by the operation of the switch hook for disconnecting said condenser from said bridge and connecting the transmitter in bridge with the receiver, means across the called line for signaling the calling line, and a manual device for removing said last means from across the called line.

l1. In a-telephone system, a calling line anda called line, automatic progressively 'movable means for connecting the two, a

. comprising a magnet and signaling current impulses -controlled thereby.

Signed by me at Chicago, Cook county. Illinois, this 16th day of October, 1913.

ALBERT AN DERSEN.

Witnesses G. YANooHowsKI, RAY STOKELY. 

